LIGHTWEIGHT CONJUGATE ACRYLIC FIBER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a lightweight conjugate acrylic fiber excellent in lightweight properties and stably producible with good process passableness, and to provide a simple method for producing the lightweight conjugate acrylic fiber. SOLUTION: This lightweight conjugate acrylic fiber comprises a sheath part composed of an acrylonitrile-based polymer and a core part composed of an acrylonitrile-based polymer and a polymer soluble in a solvent for the acrylonitrile-based polymer and insoluble in water and has voids satisfying the following formula in the core part. The lightweight conjugate acrylic fiber is produced by carrying out the solution spinning using the acrylonitrile-based polymer as the sheath component and a mixed polymer of the acrylonitrile-based polymer with the polymer soluble in the solvent for the acrylonitrile-based polymer and insoluble in water as the core component when the core-sheath type conjugate acrylic fiber is produced. 20μm>=D>=10 d (wherein, D denotes the maximum diameter of the voids present in the core part region; (d) denotes the minimum diameter of the voids present in the boundary region between the core and the sheath parts).